The EL6119 is a dual four-channel
laser diode current amplifier that
provides controlled current to both a
CD and DVD laser diode. Channels 2, 3, and 4 should be
used as the write channels, with switching speeds of
approximately one nanosecond rise/fall time. All four
channels are summed together at the IOUT output, allowing
the user to create multilevel waveforms in order to optimize
laser diode performance. The level of the output current is
set by an analog voltage applied to an external resistor
which converts the voltage into a current at the IIN pin
(virtually ground). The current seen at this pin is then
amplified to become a current source at pin IOUT.
Output current pulses are enabled when an ‘L’ signal is
applied to the WEN pin. No output current flows when WEN
is ‘H’ and additional laser diode protection is provided since
the WEN input will float high when open. Complete IOUT
shutoff is also achieved by holding the ENABLE pin low,
which will override the WEN control pins.